1. Field of the Invention
The present invention relates to a method and a device for operating a drive unit, and to a test device for testing a drive unit.
2. Description of Related Art
Methods and devices are known for operating a drive unit of a vehicle in which for at least one operating quantity of the drive unit a deviation from an initial value is represented by an adaptation value, and in which the adaptation value is determined at various times.
For example, published German patent document DE 102 61 382 describes a method for adapting the characteristic curve of an intake-manifold pressure sensor of an internal combustion engine, the characteristic curve being adapted, in particular repeatedly, for at least two different pressures in an intake manifold of the internal combustion engine.
In addition, test devices are known for testing a drive unit of a vehicle, for example in the form of an official tester or a workshop tester that reads out at least one adaptation value from an engine control unit of the vehicle, the at least one adaptation value being used as described to represent a deviation of at least one operating quantity of the drive unit from an initial value.
At the present time, only current adaptation values are determined by the engine control unit and read out from the engine control unit by the test device. Thus, it can occur that an adaptation value is determined by the engine control unit and outputted to the test device that does not correspond to the maximum or minimum adaptation value occurring in the drive unit of the vehicle. Depending on the operating quantity, for example in the summer high adaptation values may result due to the high external temperature, and in the winter correspondingly low adaptation values may result due to the cold. If only the current adaptation values are read out by the test device, the workshop evaluating the adaptation value may be misled.
In a long-term test of the vehicle manufacturer as well, it is not the maximum occurrent adaptation value or minimum occurrent adaptation value, which is an indication of quality, that is determined and read out by a corresponding test device, but rather only that adaptation value that was momentarily determined and stored by the engine control unit of the vehicle during the reading out by the test device.